If you can read music then you can notate music. Software programs do a lot of things for you (such as convert tab into standard notation as you go along, print out scores, some error checking). I use PowerTabEditor which is free and works with Windows computers but there are several other music score editors you can buy.

You might like to start with a notation editor. A free example that I use and recommend is called Musescore. There are others.

Another option would be an ABC editor. ABC is a way of coding music notation in very simple and small text files. There is a huge resource of ABC files on line and experimenting with them might help. Folk tunes are one of the easiest forms of music to read and being able to read notation is a pre-requisite to writing your own music in notation form.

It is not an impossible task but the first steps can be brain numbingly slow. Not only linking the position of notes on a stave with positions on a fretboard, you also have to work out timing in a series of summing steps.

The big trick in learning to read notation is to have a large amount of simple stuff to read. If you only have a small amount of reading material you will be in danger of playing from memory rather than actually reading. Read a tune through once and go on to the next.

At the same time experiment with some kind of software that allows you to input notation and then play it.

There are (expensive) books you can buy on style and form, but you can just get started doing it. A program like Finale already takes care of the form issues in a rough way. If you were going to submit to a publisher, you would want to clean it up quite a bit, though.

The biggest thing you'll face is making decisions about how to present something. A good rule of thumb to follow is the easier to read and interpret the better. The one mistake that I see almost every inexperienced person make is obscuring the beat in a measure. A simple thing like not writing note values across the mid point of a measure can make a huge difference in readability.

Like anything else, you can start simple and work your way up to the more complex. Copying existing music into the program is also a good way to learn the program and get a feel for how things are notated.

Does anyone have any good advice as to where I could lesrn how to write music.

I do read music to a level I’m happy with but what I’d like to do is write down my own melodies correctly and I struggle.

It maybe that what I’m asking involves significant knowledge which is long term study, but in essence I’d like to write my ideas down, so if I come up with an eight bar melody I can get it down.

Hi washy…
First of all I recommend you record things you write to your phone or a small digital recorder so you don't forget it. Recording is far faster than writing it out…writing it down can take place later.

I studied applied music theory in college, and I already knew how to read well and had been composing for a few years.

The course involved us learning to take live musical 'dictation'(listening to an 8 bar passage in 4 parts, and notating it in four passes), and we were also expected to compose and write out 8 and 16 bar exercises in four part notation a few times per week (which the teacher would play for the class).

I greatly benefited from the class.

It was certainly more comprehensive than the two things I listed above which we did weekly, and we had an amazing instructor who didn't just dispense information. He demonstrated on the piano what he was teaching during the class periods. If you want to thoroughly understand everything you are doing, then classroom is likely the best way to get there.

There is no quick path for what you want to do…even if you spend hundreds of dollars on recording software that can notate (the programs I've seen make plenty of mistakes).

Since you read music, you could create some staff paper on your own explore with writing out a melody line. You should be able to piece together the notes and values of what you are writing.

I have downloaded an ipad app to have a go on and I plan to replicate some existing melodies as well as try my own. I don’t think I’m able to take any courses etc but I will essentially learn by trial and error. I actually only want to notate ideas but obviously learn in the process.

And yes recording good ideas is something I really need to do more of.

…And yes recording good ideas is something I really need to do more of.

Hi washy
I can notate as fast as I can run the pencil, but have found that just having a Zoom H1n by my practice/play area I've captured and built on more ideas than I failed to get on paper because not staff paper was near when I had the idea.

I'm guessing if Bach were alive today, he'd have a recorder handy all the time.

I kind of feel that the stumbling block are issues such as rests and tied notes but possibly the best way forward is to get stuck into a program and try it.

I suggest - along with any theoretical study or working with a program - buying a songbook of songs that you know. Look at how those familiar melodies are notated. How do they use ties and rests?
You'll find lots in vocal melodies of pop and rock songs, maybe fewer in melodies of classical, folk or jazz tunes. That's because pop and rock vocals are usually transcribed from recordings, retaining all the phrasing used which often includes syncopation, which usually requires ties. Classical, folk and jazz tunes often have the melodies simplified so all the notes are on the beat, and ties are rarely needed.

Here's a tune in which the vocal is almost entirely syncopated:

So, lots of rests, ties and slurs.
Rests obviously indicate periods of silence, and have similar values to notes - notes and rests have to add up to the value of the bar (4 beats in this case). So the first bar has a one-beat note (quarter note), followed by a quarter-note rest and a half-note rest. Then bar 2 starts with a half-note rest before the four 8th notes.
Bar 3 has a "slur", a curved line joining two different notes. This is because the two notes cover one syllable, "la-and". Again, rests equivalent to an 8th and half note complete the bar. Notice they go in that order, and not half-note followed by 8th note - this is so the half-way point in the bar is clear. Notes and rests should never cross over beat 3.)
Bars 7-8 contain a single note stretched over two bars. I.e., the singers hold the syllable "land" for 7 quarter notes. That's what the "tie" indicates: joining the whole note to the dotted half-note. (Then a quarter note rest to allow the singer(s) to take a breath!)
The melody is then almost all in 8th notes, sometimes separated by rests (some of which are not totally necessary, see below), sometimes joined by slurs (one syllable two notes), sometimes ties (same note extended across a barline, or across beat 3.)

The phrase "mid-night creeps" could have a quarter note on "night" instead of the 8th note and 8th rest. The way they've shown it indicates a break before "creeps", of course, suggesting the singer should sing "night" shorter than he might usually. Singing this phrase more naturally wouldn't need all those rests (no need to actually breathe that often!), so this is a stylistic thing - a distinctively "staccato" effect.
The syllables "slow-" and "hearts" are syncopated - normally they'd fall on beat 1 of the bar, but are brought forward and then sustained across the barline - hence the need for the ties.
The syllable "in-" in bar 10 is two tied 8th notes; i.e., it would sound like a quarter note, but crosses beat 3, so needs to be shown as two 8ths: the second 8th is on beat 3, underlining that the syllable is syncopated - starts before the beat and holds across it. In a sense this is more complicated than a simple quarter note, but makes the timing easier to read.

NB: this is an extreme example! Very few vocal melodies would actually need notating this fussily. The point is just to show how ties, slurs and rests are employed.

__________________
"There's only two kinds of music: good and bad. I like both kinds." - Duke Ellington.

I started studying jazz at local university 4 months ago and at that time I couldn't read or write at all. In my opinion to start writing you need sense of rhythm and good relative pitch. The first one I got down to lvl sufficieñt enough for my studies using an app. There's ton of them, I'm using rhythm master for instance. Work through the exercises to get good idea where in the 4 beats the note you re hearing is and for the other part spend good time at the piano learning to hear intervals. Start with major scale, learn to recognize the sound of tonic to all 6 degrees, then work from there to more advanced stuff. Nothing you're born with, just put in the time and in a few months you'll be set, to write down whatever you hear in the bus or wherever u may be.